Microphone offers only marginal sound improvement, not worth the price charged.
The free app is totally useless.
This app doesn’t work with my iPhone 6 and iQ6 microphone. The changes in amplitude cannot be seen on their graphic representation. I would return the microphone to amazon but it does barely work with the native iPhone recorder , albeit with only a small improvement in sound quality.
I wanted this to work and invested a few hours in sorting it out to no avail. Even for free this app costs too much!